Extruding Bioplastic

The black bit in the image that looks burned (but isn't) is the sort of extrusion we want. The reason it is black is because the black part stayed inside the heating chamber part of the barrel for significantly longer (1 minute) compared to a few seconds of the grainy extrusion following the black area. This was caused by my slow loading of the bioplastic strips into the barrel, followed by my fast extrusion of the plastic.

Strips of Ag10 were placed into the barrel of a 3D printer hot end, which was heated to 220C. The bioplastic was forcefully pushed through with the help of an Allen key. The resulting bioplastic that was extruded from the 1.7mm nozzle was about 1.8mm in diameter, but after drying shrunk down to 1.7mm, which fits the dimensions of most common 3D printer filaments. The longer the bioplastic stays in the barrel, the harder it becomes, and less shrinkage occurs (after drying), meaning that this current setup would not be applicable for continuous extrusion, as you want the bioplastic to be exposed to heat for a long period of time. A real plastic extruder, that would have a much longer heating chamber would allow the bioplastic to be heated for a much longer period of time. This would be better for the extrusion of agar-based filament. As you might be able to see in the image, the areas that did not turn a darker color did not get enough heat throughout the extrusion process. These areas a weaker, and easily break off. They are also grainy and don't have a uniform diameter.

Note that Ag10 includes a plasticizer, meaning that this filament is more flexible than it should be. This experiment will be redone with Ag13 as the medium, to create a harder and better-performing filament. Ag13 also has more agar, so it would be interesting to see the results and how it turns out.